Are you getting enough sleep?

Find out when is the best time to get up and do you all need a minimum number of hours asleep.

Research at the University of Westminster has confirmed something that most of us already knew – there are people who do mornings and there are people who don't.

There is a difference between those who leap out of bed early and throw themselves straight into demanding activities and those who have to drag themselves into consciousness, needing a prolonged warm-up period before they can face a coffee let alone the business of the day.

Are early birds physically different?

Psychologist Dr Angela Clow, who did the research, asked 42 volunteers to take saliva samples eight times during the day for two days, beginning when they first woke up. The waking times ranged from an uncomfortable pre-dawn 5.22am to the more laid-back hour of 10.37am.

Half of the group were awake by 7.21am and they were found to have higher levels of cortisol, the body's main stress hormone, than those who lingered longer in the sack.

'These results are interesting,' says Dr Angela Clow because they provide a physiological basis for the often-reported difference between early and late risers.

'Early awakening has been associated with greater powers of concentration, being busier and experiencing more hassles through the day, as well as having more anger and less energy at the end of the day.

'On the other hand, late wakers were more leisurely and less busy. It is possible the cortisol may contribute towards these differences in temperament because it is known to influence mood and concentration,' she said.

In follow-up research over a 10-week period, it was found that the early risers were more likely to suffer from muscle aches, colds, headaches and mood swings.

When is the best time to get up?

There is no optimum time to get up in the morning, says Dr Clow, but she does concede that if you do feel stressed, an extra 20 or 30 minutes sleeping in could make a huge difference.

You just have to try it and see, she says.

Do we all need a minimum number of hours asleep?

The one area about sleep where the experts are in full agreement is that there is no minimum number of hours that we should all spend sleeping before endangering our health.

Some of us can get by on six hours without feeling any ill-effects and others claim to a minimum of eight. It is a matter of horses for courses.

One study has show that 8.1 hours of sleep per 24-hour period is the average requirement for adults. But the need for sleep in the group ranged from just 6 to 10 hours.

Margaret Thatcher famously boasted that she only needed five hours in bed when she was Prime Minister. Although she made millions feel guilty for lying in, it isn't that unusual for people in their 60s to cope with a short night's sleep. Most of us sleep less as we get older.

Do people sleep less than they used to in the past?

It is a myth of our times that we are all so active, busy and stressed that we are sleeping less than a century ago.

According to Professor Jim Horne of the Sleep Research Centre, Loughborough University, it is simply not true.

'There is no evidence the Victorians slept longer. I suspect many people slept less in the early 1900s because they worked longer hours and had poorer sleeping conditions,' said Dr Jim Horne.

Would it be better for us all to sleep more?

Research has shown according to Dr Jim Horne that if we are given the opportunity to sleep more we will do so.

In a study it has been shown that if people stay in bed two hours longer than in their normal routine, they will on average sleep for an extra hour.

Is this proof that we are all sleep deprived? Dr Horne doesn't think so. He points out that given the opportunity, most of us would eat more, drink more and have more sex.

But this doesn't mean we have been deprived or have unfulfilled needs.

'Early to bed, early to rise makes a man healthy, wealthy and wise.' Is the old adage true?

Benjamin Franklin, Thomas Edison and Samuel Johnson all went along with this lifestyle advice but it is not supported by modern scientific research.

At Southampton University in a study published in the British Medical Journal involving 1229 men and women over a 25-year period it was found that those who burned the mid-night oil and slept in the following morning suffered no ill effects.

They also proved to be slightly wealthier than the early risers and no less healthy.

Surprisingly, it was observed that people who slept longer, whatever time they retired, died younger. If this is not justification for teenage clubbing in Ibiza, what is?

How do you decide how long to sleep?

When pinned down, scientists feel between seven and eight hours sleep a night is enough for most of us.

As Dr Horne sums it up: 'There is a basic amount of sleep we all require to function comfortably in our daily life. Beyond that, it is a very enjoyable time-filler, but it is not essential.'

Dr Chris Hanning, director of the Sleep Disorders Clinic at Leicester General Hospital, says he believes in the simple test of whether you feel sleepy during the day.

This he says is often ignored by those who complain of sleep problems. 'If you are awake and alert in the day, you are obviously getting enough sleep,' says Dr Hanning.

If you do suffer from an after lunch energy dip which happens to all of us from time to time, it is easily taken care of. There is no need to spend hours more in bed or worry yourself sick.

A 10-minute catnap at lunchtime should do the trick and leave you refreshed for the rest of the day.

Dr Adrian Williams, consultant physician at St Thomas's Hospital, London, and Director of their Sleep Disorder Centre, says: 'We all need so many hours sleep in each 24-hour cycle and it doesn't matter how we get. In Mediterranean countries it isn't uncommon to sleep for five hours at night and two in the afternoon. That is the same as having a full eight hours at night. Some people make up the deficit by having little dozes throughout the day.

'If you aren't getting enough rest, you will become sleepy at about 4.00pm. This is nothing to do with having a big lunch. It is part of the body's daily rhythm. That and 6.00am are the times when most car crashes happen by people falling asleep at the wheel,' says Dr Williams.

You can't bank your sleep in advance, he says but you can make it up afterwards. And the great news is that anyone who feels better after sleeping in at the weekend is doing the right thing.

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